In Editorial Articles, Original Blog Content

By: Tom Johnson

September 27, 2011

Grid operators could tap into car’s batteries when vehicle is parked and plugged in.


Here’s a novel thought: Instead of draining electricity from the power grid, electric vehicles can become a mobile source of generating power, especially at times of peak demand.

It’s a concept that NRG Energy, a Princeton-based company with a growing renewable energy portfolio, and the University of Delaware are promoting, saying they plan to embark on a commercial venture that will enable owners of electric vehicles to sell electricity from the batteries of parked cars into the power grid, a technology developed by the school.

The idea, if commercially feasible, would help promote consumer acceptance of electric vehicles by lowering costs to fleets that decide to purchase the low-emission vehicles, as well as electric vehicle owners. Further, the vehicles would be a cleaner source of electricity to power homes and businesses, according to university officials and the company.


Denise Wilson, president of NRG’s Alternative Energy Services, described the technology, which offers a two-way interface between electric vehicles and the power grid, as the next logical step in the electrification of the transportation network. “It’s one more way electric vehicle owners can commit to a sustainable energy future and get paid for it at the same time,” she said.

NRG Energy has been in the forefront of trying to build the infrastructure for electric vehicles, installing charging stations in and around Houston in a pilot project. The company recently opened its first station in Houston; it enables owners to recharge their vehicles in as little as 10 minutes, an advancement that helps overcome one of the biggest concerns about plug-in vehicles — what’s known as range anxiety, concern over how far the vehicles could travel.

The new technology, pioneered by University of Delaware professor Willett Kempton, would allow electric vehicle owners to sell battery storage back to the electric grid while the electric vehicle is plugged in—at no risk or inconvenience to daily driving needs.

To participate, electric vehicle owners would enroll in a special program. Once signed up and plugged in, the vehicles would communicate with the grid and let grid operators take power from connected electric vehicles during peak usage periods.

Electric vehicle owners would be able to schedule in advance any times their vehicles need more charging than usual, such as before an unusually long trip. Similarly, they could designate what minimum level of charge they want to maintain at all times. The new venture, dubbed eV2g, would collect payments from the grid operator and pay owners of electric vehicles for making their vehicles available.

“Energy research, including grid-integrated vehicles, is an important priority for the University of Delaware,” said David Weir, director of the university’s office of economic innovation and partnerships, the economic development arm of the school. “The energy storage inherent in automobiles is staggering. If all the automobiles in the U.S. were electrified it would be enough to power the entire U.S. for half a day.”

That could be beneficial for New Jersey, which has been saddled with very high energy costs because of congestion on the grid. By some estimates, consumers pay over $1 billion a year more than their counterparts in other states because of constraints on the power grid.

High Hurdles

Still, the commercialization of the technology faces steep hurdles, according to analysts. Paul Patterson, an energy analyst at Glenrock Associates in New York City, said storage has been one of the biggest stumbling blocks in the development of electric vehicles, as well as renewable energy technologies such as solar and wind, which are intermittent sources of electricity.

But Kempton said the operators of the regional power grids, particularly PJM Interconnection, which oversees the largest power grid in the nation, serving more than 50 million people, have been “wildly enthusiastic about the project and its opportunities.

Electricity grid operators rely on resources that can help provide or absorb bursts of energy to keep the grid running smoothly — a requirement that is likely to become more urgent with increased reliance on intermittent sources of energy.

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